The present invention relates to fluid containers, such as replaceable ink tanks for ink jet printers. In particular, the invention relates to reducing ink leakage when such a container is opened under atmospheric conditions different from the conditions under which the container was filled.
In different types of printing, such as ink jet printing, drops of ink are ejected from nozzles in an ink jet printhead in a specified pattern to form an image on a print medium. Examples of ink jet printing include thermal ink jet and piezoelectric ink jet. Both of these printing technologies are well understood by those skilled in the art. In ink jet printing, the ink is supplied to the printhead from a ink supply system. For a liquid ink printer, the ink supply system often includes one or more liquid ink containers that store the ink in liquid form until it is delivered to the printhead. In certain applications, the ink container and the printhead are formed as a single unit. In other applications, the ink container is replaceable apart from the printhead.
Replaceable ink containers are typically filled with liquid ink at a manufacturing site and sealed against leakage. The filled ink container typically has some amount of air trapped within the container when it is sealed. The sealed container is then shipped to the end user. The end user unseals the container, and installs the container in a printer for use.
A recurring issue with liquid ink containers is that the atmospheric conditions at the end user""s location may differ from the atmospheric conditions at the manufacturing site at which the ink container was filled. Such different atmospheric conditions may cause the pressure of the air trapped inside the ink container to be higher than the ambient pressure at the user""s location. In such a circumstance, the higher pressure inside the ink container may cause ink to squirt from the container when the user unseals the ink container.
A method of opening a liquid ink container that has a capillary chamber and a free fluid chamber includes lowering the pressure in the free fluid chamber by expanding the volume of the free fluid chamber. After lowering the pressure in the free fluid chamber, the method includes opening the capillary chamber to the ambient environment. In one particular implementation, expanding the volume of the free chamber comprises dislocating outward a portion of the wall of the free fluid chamber.
A fluid container includes a housing formed of a plurality of container walls, with a fluid port through one of the container walls. An expansion element for the housing comprises a deformable wall portion of one of the container walls. An opening element is attached to the deformable wall portion for moving the deformable wall portion from an inner position to an outer position to expand the interior volume of the housing. A seal covers the fluid port.